Replace boiler coil

Daniel Holzman

I have a fifty year old oil fired boiler. Recently the TPV went off. I assumed the expansion tank was full, so I drained it, filled with air, and restarted the boiler. Fifteen minutes later, the TPV went off again. I checked the boiler makeup valve, this is relatively new since I replaced it three months ago. Anyway, I shut the glove valve just to make sure the filler valve was not the problem, sure enough the boiler pressure continued to increase.

I believe the problem is a leaky indirect heating coil in the boiler that feeds my storage tank. I shut the coldwater makeup valve to the tank, and the problem stopped. Course I have no hot water.

The coil has no stamp on the steel face plate. It is a vertical plate, fourteen 1/2 inch bolts, approximately 12 inches high, 3 inches wide. I do not believe I want to replace this item myself, the bolts look pretty rusty, I am concerned they will snap if I try to remove them.

Anyone have experience replacing an indirect (tankless) coil, and can offer suggestions as to whether this is a DIY or a professional only job? And where can I purchase a replacement coil for an older boiler? Any recommendations on type of coil, techniques for replacement, would be welcome.

NHMaster

50 year old boiler. Let's start at the start. You probably can get a replacement coil for the boiler, there are several companies that produce aftermarket coils. But.... it's going to cost you a couple hundred bucks at the very least and a 50 year old boiler is not worth putting the money into. In fact, if the boiler is 50 years old, it's time to replace it. In the mean time, look into an electric or gas fired water heater or if you have the money, replace the boiler and get an indirect storage tank for it.

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COLDIRON

My neighbor just last week replaced his 50 year old boiler the problem and description was was exactly like yours. A piece of metal plate about 12" long by 3" was leaking at the domestic water coil. The date was 1967 found on the small plate. Got the old dinosaur out and the new one in he's very happy. Progress things don't last forever not even us.